Pretty basic question here: I am wiring a building that will have a combination of LEDs that have resisters factory installed and ohers that need a resister. During the process, I thought I would measure the voltage before the resister, and after- assuming there would be a drop caused by the resister. Nope. 13.5 AC comes out 13.5 AC with or without the resister. Using a 9V DC battery- same thing.
I must be missing something??
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Basic question here too, I am not 100% clear on your circuit but you need current flow to get a voltage drop.
Rather than measuring the voltage, measure the ohms of resistance across the resistor. If that is right for the source DC voltage, you're okay. This assumes the resistor has high enough power handling capacity (watts) - not usually an issue with LEDs. But should not be AC for LEDs.
Thanks to all who responded. I plan to convert AC to DC for the lighting circuit.
Resistors only drop voltage when current is flowing through them.
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